2 files changed, 7 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index 06dee3962f..857783b06e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Nov 12 11:16:32 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* io.c (ioctl_narg_len): Linux doesn't have IOCPARM_LEN macro, but
+	  has _IOC_SIZE. support it.
+
 Sat Nov 12 11:13:18 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* io.c (rb_ioctl): don't expose our sanity check value to ruby script.
diff --git a/io.c b/io.c
index 38638a18db..a351737877 100644
--- a/io.c
+++ b/io.c
@@ -7908,6 +7908,8 @@ ioctl_narg_len(int cmd)
 #endif
 #ifdef IOCPARM_LEN
     len = IOCPARM_LEN(cmd);	/* on BSDish systems we're safe */
+#elif defined(_IOC_SIZE)
+    len = _IOC_SIZE(cmd);
 #else
     len = 256;		/* otherwise guess at what's safe */
 #endif